Linings for rotary mills

ABSTRACT

A lining for rotary mills comprising lifting and lining elements renewable by rotation and of a star-shaped cross section having substantially uniform points. The elements of the lining may have inner cooling passages constituted by tubes. The tubes may serve as rotational axes and supporting elements for the elements of the lining.

nited States Patent Hallerback Aug. 1, 1972 [54] LININGS FOR ROTARYMILLS [56] References Cited [72] Inventor: gtigdbennart Hallerback,Lunda, UNITED STATES PATENTS we en 1,470,597 10/1923 Denny etal..241/183 X [731 Asslgnee- 53%? u g g g' 2,887,276 5/1959 Minarik..24l/67 e we 2,909,335 10/1959 Janelid ..241/183 [22] Filed: Sept. 24,1970 3,194,506 7/1965 Bourne et al ..241/ 182 X 21 A l.N 75125 1 pp 0Primary Examiner-Robert L. Spruill Attorney-Beveridge & De Grandi [30]Foreign Application Priority Data Sept. 25, 1969 Sweden ..l3162/69ABSTRACT A lining for rotary millscomprising lifting and lining "241/51/ elements renewable by rotation and of a star-shaped [58] Field 182cross section having substantially uniform points. The

elements of the lining may have inner cooling passages constituted bytubes. The tubes may serve as rotational axes and supporting elementsfor the elements I of the lining.

18 Claims, 7 Drawing Figures PATENTEUAUI; 1 4912 sum 1 or 4 7 4 (Emmer-H/uzm sic/e PATENTEDAUG 1 I972 saw u. nr 4 FIGS LININGS FOR ROTARY MILLSWhen rotary mills are used for grinding of mostly highly abradingmaterial the inner circumferential surface and side walls of the rotarymill barrel will be subjected to substantial wear. This wear unfavorablyaffects the operating economy of the mill since the efficiency of themill is greatly reduced when the lifter or driver system of the sheetmetal barrel becomes worn. This occasionslong break-downs anddisturbances as well as expensiverepairs. To improve the operatingeconomy of the mill itis lined with some wear-resistant material, suchas rubber. The difficulties which, however, arise with a conventionallining in the mills first of all is a non-uniform wear of the liningelements and secondly the difficulty of keeping the temperatures at sucha low level that the lining elements will not suffer from overheating.This is particularly troublesome in grinding dry materials. r

One object of this invention is to provide a lining for mills, in whichworn-out elements can be rapidly exchanged by extremely simple measures.Another object of this invention is to provide an efficient coolingsystem for the lining elements.

The above objects are realized by the present invention which provides alining for a rotary mill barrel comprising lining elements made from awear resistant material and mounted soas to protect the inner side ofthemill barrel, lifter and driver'elements made from a wear resistantmaterial and constituting some of said lining elements, said lifter anddriver elements projecting from the remaining elements, wearing portionson said lifter and driver elements, said lifter and driver elementshaving a substantially star-shaped cross section the points of whichconstitute said wearing portions, mounting means for said lifter anddriver elements permitting renewal of the wearing portion of said lifterand driver elements by simple rotation of said elements.

According to the invention, the lifter and driver elements are formedsubstantially according to two dif ferent types, one type servingprimarily as a protection for the sheet metal mantle of the millwhile'the other type, apart from its mantle protective function, alsoserves as a driver and lifter for the charge of the mill, and at leastone of the elements of the lining is formed with a star-shaped cross.section having substantially uniform points, and said lining elementwhich preferably is a driver and lifter element is so adjustable byrotation that only one of the projecting points of the star-shapedsection is subjected to wear, whereby the wearing portion of thestar-shaped lining section element is easily renewable by simplerotation of the respective element.

Further objects of the invention and the features of and the advantagesgained by the invention will become apparent from the followingdescription, in which reference is made to the accompanying drawings inwhich:

FIG. '1 is a perspective view and cross section of a ball mill;

FIGS. 2-6 are sections of alternately formed mantle segments for saidmill;

FIG. 7 is a perspective view illustrating various possibilities ofarranging cooling systems in the mill.

FIG. 1 shows a mill consisting of a cylindrical mantle 1 with end walls2 and 3, respectively. The material 4 to be crushed or ground issupplied to the mill through a connecting socket or inlet 5 and iscarried away from the mill through a discharge socket or outlet 6. Thecylindrical mantle surface 1 of the mill in the outermost layer thereofconsists of a supporting steel structure 8. To protect the outer steelmantle from wear the latter is coated internally with two differenttypes of lining panels 9, 10 made from some type of wear resistantmaterial, such as rubber. One type of lining panels or elements 9 hasthe main purpose of protecting the steel structure while the other typeof lining elements 10, apart from their protective function alsoconstitutes drivers and lifters for the material to be ground orcrushed. When the mill is in operation there always arises a higher wearof said lifter elements 10, whereby the efficiency and performance ofthe mill are reduced. For this reason, the'lifter element 10 accordingto this invention has been given a star-shaped cross section, in thepresent instance with three points, so that it is possible to introducea new lifter into the mill proper by rotating the element through onedivision. In that way,

the driver or lifter elements can be utilized three times before theyare so worn out that they have to be dispensed with. FIGS. 2-6 show morein detail how the lining elements proper may be arranged.

In FIG. 1, the. lifter element 10 has been formed with a central hole ortube 11 which is fixedly or movably centered in bothend walls 2 and 3.Liquid coolant or cooling air can be supplied through the tubes, wherebythe operatingv temperature of the wearing elements is considerablylowered, which makes for an appreciably increased life of said elements.If desired, the wearing elements 9 also can be provided with coolingpassages according to the above system, see in FIG. 3. The loweredtemperature and the improved degree of exploiting the lining elementsgives the mill in total a very good operating economy.

FIG. 2 shows a cross section through part of the outer barrel of themill. The lifter elements 12 are in the form of regular stars havingvthree points 13, 14 and 15. The lifter element 12 will become accessiblewhen the door 16 of the outer sheet metal mantle l is opened. If at aninspection of the driving and lifting portion 13 of the lifter elementthe said portion shows a wear such as that marked by the dotted line 17the driving and lifting effect of the element 12 is so low that thedriving and lifting portion must be exchanged. To do this, the elementis withdrawn, rotated through counterclockwise and then reintroducedinto the gap between the two wearing elements 9, the function of thelifter element being again as good as if an entirely new unit had beeninserted. After the rotation of the lifter element the door 16 isreplaced, spring elements 18 keeping the lifter element 12 in correctposition. At the center of the lifter element 12 there is provided alongitudinal passage or a longitudinal tube 19 through which a liquidcoolant or cooling air is supplied. The lining elements 9 between thelifter elements 12 are made in the form of panels in FIG. 2 and have anembedded fastening metal sheet 20 which can be secured by bolts in aknown manner against the barrel 1. The lining elements 9 'must be madeso thick in their wear resistant portion that their life on the wholecorresponds to the time it takes to wear down all three drivers andlifters 13, 14 and 15 of the element 12.

FIG. 3 mainly shows the same type of lining element as FIG. 2, with thedifference, however, that the lining elements 9 have two longitudinaltubes 21 which are connected to the end walls of the mill on the sameprinciple as the tube for the rotatable lifter elements 12. By thisarrangement the entire lining of the mill can be given a much loweroperating temperature than what is the case in conventional milllinings.

FIG. 4 shows a special combination of rotatable driver and lifterelements 12 and lining elements 9. The driving and lifting portion 13 ofthe elements 12 in this embodiment to a certain extent constitute partof the lining element 9 since the latter has been designed with aninclined supporting portion 14 which braces the rear side of the drivingand lifting portion 13. As a result, the driving and lifting portion 13will have a greater stability andsupporting ability. Should it prove atan inspection that the wear of the driving and lifting portion 13 is solarge as illustrated by way of example by the dotted line 22 the lifterelement is rotated whereby a practically new lining is obtained. Bybuilding a mill lining in this way use can be made of a very good rubberquality for the heavily stressed and worn lifter elements, whereas theintermediary lining elements 9 may be made in a cheaper and economicallymore advantageous quality.

As will appear from FIG. self-setting or self-adjusting mantle elements23 can be mounted between the lifter elements 12. These self-setting orself-adjusting elements in their upper parts have a longitudinal tube24, about which the element 23 is movable. This arrangement may be ofadvantage in the total mounting of the lining elements and providessimple and efficient cooling properties on the same principle as for therotatable lifter element.

Like the earlier FIGS., FIG. 6 shows a number of lifter elements 12.Provided between these lifter elements are similar rotatable mantleelements 25 which can thus also be renewed three times according to thedegree of wear.

FIG. 7 very diagrammatically shows how the cooling systems through thelining elements can be caused to function. At 26 there is shown quitesimply how the central tubes or holes freely open on the outer side 27of the mill end wall. At the rotation of the mill in the direction ofthe arrow air under pressure or cooling water 28 may be injected whenthe tube mouths go past a fixed nozzle 29. A type of self-circulationfor water may be arranged, for example as shown at 30 with a number ofinlet nozzles directed in opposition to the direction of rotation of thebarrel. If said inlet nozzles are extended as shown at 31 they will beable to collect so much water when passing a water reservoir 32 that asuitable speed of the flow of cooling water may be obtained through thecentral tubes. Considerably more developed cooling arrangements maycertainly be provided, but the systems shown and described are merelymeant to aim at indicating the basic principle of the cooling function.

What I claim and desire to secure by Letters Patent 1. A lining for arotary mill barrel comprising lining elements made from a wear resistantmaterial and mounted so as to protect the inner side of the mill barrel,lifter and driver elements made from a wear resistant material andconstituting some of said lining elements, said lifter and driverelements projecting from the remaining lining elements, wearing portionson said lifter and driver elements, said lifter and driver elementshaving a substantially star-shaped cross section the points of whichconstitute said wearing portions, mounting means for said lifter anddriver elements permitting renewal of the wearing portion of said lifterand driver elements by simple rotation of said elements.

2. A lining as claimed in claim 1 wherein at least the star-shapedrotatable lining elements have a central through tube which may be usedfor cooling the elements.

3. A lining as claimed in claim 2 wherein the central tube is mounted inthe end walls of the rotary mill barrel in such a way that the rotatablestar-shaped lining element can perform a radial movement.

4. A lining as claimed in claim 1 wherein the rotatable lining elementsare accessible from outside the periphery of the mill barrel by suitablyarranged door elements.

5. A lining as claimed in claim 1 wherein the rotatable lining elementsare resiliently clamped from the outside towards the center of the millbarrel so that large tolerances may be taken up at the contact with theremaining lining elements.

6. A lining as claimed in claim 1 wherein both the star-shaped liningelements constituting rotary drivers or lifters as well as mantle liningelements which are arranged between the star-shaped lining elements areprovided with longitudinal central tube systems for cooling the liningmaterial.

7. A lining as claimed in claim 6 wherein the mantle elements arrangedbetween the star-shaped lining elements are rotatably mounted about athrough tube passing longitudinally of said mantle elements and servingas a cooling tube for the lining material.

8. A lining as claimed in claim 6 wherein said mantle elements like saidlifter elements, are formed with a star-shaped cross section and areadjustable by rotation into different working positions.

9. A lining as claimed in claim 2 wherein said central tubes arearranged to receive coolant, through injection nozzles located at theend wall portions of the mill barrel and directed towards said portions.

10. A lining as claimed in claim 9, wherein tubular nozzles provided inthe end walls are so formed for the cooling operation that therotational speed of the mill results in a circulation effect in the tubesystem of the lining elements.

11. A lining as claimed in claim 9 wherein tube connections for coolingat the mill end walls are extended peripherally in such a way as to beable to take up on their rotation a suitable amount of liquid coolant tocool the tube system extending through the lining elements.

12. A lining as claimed in claim 7 wherein said through tubes aremounted in the end walls of the rotary mill barrel so that the rotatablelining elements can perform a radial movement.

13. A lining as claimed in claim 7 wherein the rotatable mantle liningelements are accessible from outside the periphery of the mill barrel bysuitably arranged door elements.

14. A lining for a rotary mill barrel comprising lining elements madefrom a wear resistant material and mounted so as to protect the innerside of the mill barrel, lifter and driver elements made from a wearresistant material and constituting some of said lining elements, saidlifter and driver elements projecting from the remaining liningelements, wearing portions on said lifter and driver elements, some ofsaid lifter and driver elements having a substantially star-shaped crosssection the points of which constitute said wearing portions, mountingmeans for said some of said lifter and driver elements permittingrenewal of the wearing portion of said some of said lifter and driverelements by simple rotation of said elements.

15. A lining as claimed in claim 14 wherein some

1. A lining for a rotary mill barrel comprising lining elements madefrom a wear resistant material and mounted so as to protect the innerside of the mill barrel, lifter and driver elements made from a wearresistant material and constituting some of said lining elements, saidlifter and driver elements projecting from the remaining liningelements, wearing portions on said lifter and driver elements, saidlifter and driver elements having a substantially star-shaped crosssection the points of which constitute said wearing portions, mountingmeans for said lifter and driver elements permitting renewal of thewearing portion of said lifter and driver elements by simple rotation ofsaid elements.
 2. A lining as claimed in claim 1 wherein at least thestar-shaped rotatable lining elements have a central through tube whichmay be used for cooling the elements.
 3. A lining as claimed in claim 2wherein the central tube is mounted in the end walls of the rotary millbarrel in such a way that the rotatable star-shaped lining element canperform a radial movement.
 4. A lining as claimed in claim 1 wherein therotatable lining elemenTs are accessible from outside the periphery ofthe mill barrel by suitably arranged door elements.
 5. A lining asclaimed in claim 1 wherein the rotatable lining elements are resilientlyclamped from the outside towards the center of the mill barrel so thatlarge tolerances may be taken up at the contact with the remaininglining elements.
 6. A lining as claimed in claim 1 wherein both thestar-shaped lining elements constituting rotary drivers or lifters aswell as mantle lining elements which are arranged between thestar-shaped lining elements are provided with longitudinal central tubesystems for cooling the lining material.
 7. A lining as claimed in claim6 wherein the mantle elements arranged between the star-shaped liningelements are rotatably mounted about a through tube passinglongitudinally of said mantle elements and serving as a cooling tube forthe lining material.
 8. A lining as claimed in claim 6 wherein saidmantle elements like said lifter elements, are formed with a star-shapedcross section and are adjustable by rotation into different workingpositions.
 9. A lining as claimed in claim 2 wherein said central tubesare arranged to receive coolant, through injection nozzles located atthe end wall portions of the mill barrel and directed towards saidportions.
 10. A lining as claimed in claim 9, wherein tubular nozzlesprovided in the end walls are so formed for the cooling operation thatthe rotational speed of the mill results in a circulation effect in thetube system of the lining elements.
 11. A lining as claimed in claim 9wherein tube connections for cooling at the mill end walls are extendedperipherally in such a way as to be able to take up on their rotation asuitable amount of liquid coolant to cool the tube system extendingthrough the lining elements.
 12. A lining as claimed in claim 7 whereinsaid through tubes are mounted in the end walls of the rotary millbarrel so that the rotatable lining elements can perform a radialmovement.
 13. A lining as claimed in claim 7 wherein the rotatablemantle lining elements are accessible from outside the periphery of themill barrel by suitably arranged door elements.
 14. A lining for arotary mill barrel comprising lining elements made from a wear resistantmaterial and mounted so as to protect the inner side of the mill barrel,lifter and driver elements made from a wear resistant material andconstituting some of said lining elements, said lifter and driverelements projecting from the remaining lining elements, wearing portionson said lifter and driver elements, some of said lifter and driverelements having a substantially star-shaped cross section the points ofwhich constitute said wearing portions, mounting means for said some ofsaid lifter and driver elements permitting renewal of the wearingportion of said some of said lifter and driver elements by simplerotation of said elements.
 15. A lining as claimed in claim 14 whereinsome remaining elements are also rotary elements of star-shapedconfiguration.
 16. A lining as claimed in claim 14 wherein at least saidstar-shaped rotatable lining elements have a central through tube whichmay be used for cooling the elements.
 17. A lining as claimed in claim15 wherein said star-shaped remaining elements have a central throughtube which may be used for cooling the elements.
 18. A lining as claimedin claim 16 wherein said rotatable lining elements are accessible fromoutside the periphery of the mill barrel by suitably arranged doorelements.